4 in 1 Mode: This alarm has 4 modes. 1. Timed alarm (if the door is kept open for 3/15/30/60 seconds, "Di-Di-Di" sound from 0dB to 108dB) 2. General alarm (if the door is closed, the alarm stops); 3. Continuous alarm (Continue to alarm when the door is closed); 4. Open the door bell (the sound of inchDingDonginch will be heard when the door is opened) Loud 108dB Siren: Door and window siren help effectively deter intruders/thieves with a loud 108dB siren. You can easily set a suitable mode according to your needs. EASY INSTALLATION: Simple peel and stick installation, easily installs on most freezers/refrigerators or any door without any tools. Package includes 2 Refrigerator Alarms, 2 Magnetic Strips, Double Sided Sticker, User Manual. Electronic instructions are on the eighth picture. Installation Notes: Be sure to turn off the alarm and magnetic strip, and the installation distance between them should not exceed 0.78 inches. The 2 parts must be aligned by their alignment arrows. 2 years on 2 AA batteries. (Batteries not included) Wide range of uses: Magnetic trigger door alarm sensor protects home through door and window entrances, suitable for door sliders in safes, cabinets, freezers, refrigerators, swimming pools, shops, offices, apartments, hotels, etc. Number of pieces delivered: 2